The Vortex Viper PST (Precision Shooting Tactical) Rifle Scope comes with features that are typically only included on scopes in a much higher price range. The optics are fully multi-coated and deliver beautiful detail and color while transmitting 95% of available light. The tactical turrets have audible clicks which allow for precise adjustments to windage and elevation and the tube is purged with Argon gas to eliminate internal fogging and extend the life of the optics. A lifetime factory warranty is included.